This invention pertains to the art of infeed mechanisms, and more particularly to infeed conveyors for stackers such as newspaper or signature stackers that receive a lapped or imbricated stream of sheet products. The invention is particularly applicable to infeed conveyors that form a non-planar or V-shaped configuration to the product as it passes therethrough and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be advantageously employed in other environments and applications where greater control of sheet-like products or articles is required.
A commercially successful stacker is shown and described in U.S. Patent No. 4,162,733. The '733 patent describes particular details of the infeed mechanism which includes a set of rollers disposed in a V-shaped configuration by mounting generally cylindrical rollers on inclined shafts. As described therein, the infeed mechanism of this commercial device includes a set of flexible continuous loop members such as coil spring wires that extend around the rollers. The rollers include plural circumferential grooves that receive the coil spring wires. Upper and lower conveyors receive the stream of newspapers or similar flat articles. Typically, the lower conveyor can be pivoted in a downward fashion to define a dump gate if a jam condition is detected during operation. Once the jam is cleared, or during normal operation, the second or lower conveyor is brought into an upper, operative position where it is properly spaced beneath the upper conveyor to receive the sheet products therethrough.
The upper and lower V-rollers impart a non-planar or V-shaped configuration to the products. As is well known in the art, bending a sheet product facilitates handling by providing better alignment, feeding, enhanced rigidity, uniform handling, and the like by stiffening the sheet products.
U.S. Pat. No. 4,964,627 describes another arrangement for forming sheet product into a V-shaped configuration. Specifically, different length and different diameter rollers are arranged on cooperating shafts to define the V-shape necessary to enhance the stiffness or rigidity of the sheet product. More particularly, the shafts are disposed in generally horizontal, parallel relation. An outer pair of elongated, small diameter rollers are mounted on the first shaft. A central enlarged diameter, shortened roller is interposed between the outer rollers. The reverse configuration is provided on the second shaft. That is, the pair of outer rollers have an enlarged diameter and are relatively short in length while the central roller is elongated and has a small diameter. Thus, when the first and second shafts are placed in operative relation, the respective outer rollers and central rollers are aligned in opposed relation and a generally V-shaped configuration is defined. A set of belts are received around the rollers to define the endless loop members of the upper and lower conveyors.
One undesirable aspect of this arrangement is that a multiplicity of rollers must be maintained in inventory. That is, different sized rollers are necessary to impart the V-shaped configuration to the product stream in accordance with the teachings of that patent. At least two sizes of rollers are used and, therefore, an inventory of at least two sizes of rollers are required. This burdens the supplier who must maintain a sufficient supply of rollers on hand. Discounts that may be available if all the rollers were identical in size may not be obtained by manufacturer.
Accordingly, it has been found desirable to provide an alternative apparatus and method for forming a V-shaped configuration in sheet products that overcomes the above-noted problems in an economical, effective manner.